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141.
Abstract

A new sulfonyl derivative (C26H25N3O2S2), N’-(4-(3-methyl-3-phenylcyclobutyl)?3-phenylthiazol-2(3H)-ylidene)benzenesulfonohydrazide, was prepared from a mixture of benzenesulfonylhydrazide and phenylisothiocyanate in ethanol. The 3?D crystal structure, unit-cell dimensions, space group and crystal system of compound were investigated by single-crystal X-ray diffraction (SCXRD). FT-IR spectrum in solid state was observed in the region 4000–400?cm?1 and the 1H and 13C NMR spectra were recorded in CDCl3 solution. In order to support the experimental results, the molecular geometry, vibrational frequencies, 1H and 13C chemical shifts in the ground state have been calculated by using the density functional method (DFT/B3LYP) together with 6-311?G+(d, p) basis set. A good linear correlation between experimental and theoretically predicted structural and spectral parameters was observed (R2~0.9).  相似文献   
142.
The reaction of the Schiff base salicylideneaminopyridine with [M(sac)2(H2O)4] · 2H2O, where M is copper(II) or zinc(II), and sac is the saccharinate anion, results in the formation of the new tris(saccharinato) complexes ApyH[Cu(N-sac)2 (O-sac)(H2O)2] (1) and ApyH[Zn(N-sac)3(H2O)] (2), which have been characterized by elemental analyses, magnetic measurements, FT-IR spectroscopy, thermal analysis and X-ray diffraction. The Schiff base did not coordinate to the metal ions, but decomposed during the reaction, forming a 2-aminopyridinium cation ApyH, which remained outside the coordination sphere as a counter ion. (1) and (2) are the first examples of mononuclear tris(saccharinato) complexes of copper(II) and zinc(II). Both complexes are isomorphous with the triclinic space group P-1, (1) consisting of an ApyH cation and a [Cu(sac)3(H2O)2] anion in which the copper(II) ion has trigonal bipyramidal surroundings. The sac ligands in (1) exhibit unusual and non-equivalent coordination, behaving as ambidentate ligands. One of them coordinates to the metals through the carbonyl oxygen atom, while the other two sac ligands are bonded to the metals via the imino nitrogen atom. The zinc(II) ion in (2) is tetrahedrally coordinated by three N-donor sac ligands and an aqua ligand. The crystal structures of (1) and (2) are stabilized by intermolecular hydrogen bonds and aromatic – stacking interactions.  相似文献   
143.
Mediterranean Journal of Mathematics - A variant of the Jensen–Mercer operator inequality is proved for a superquadratic function and positive linear operators on a Hilbert space using a...  相似文献   
144.
Journal of Thermal Analysis and Calorimetry - In this study, the oxidative polymerization of orcinol monohydrate using different oxidants such as NaOCl, H2O2, and air was investigated....  相似文献   
145.
Journal of Thermal Analysis and Calorimetry - In this study, jet impingement heat transfer characteristics for a layered nanofluid and porous domains under the effects of inclined uniform magnetic...  相似文献   
146.
This work presents a sensitive and rapid analytical method for the determination of oxcarbazepine in human plasma and urine samples. A vortex-assisted switchable hydrophilicity solvent-based liquid phase microextraction (VA–SHS–LPME) was used to preconcentrate oxcarbazepine from the samples before the determination by gas chromatography mass spectrometry. The switchable hydrophilicity solvent was synthesized by protonating N,N-dimethylbenzylamine with carbon dioxide to make it totally miscible with an equivalent volume of water. Parameters of the VA–SHS–LPME method including volume of switchable hydrophilicity solvent, concentration/volume of sodium hydroxide and vortex period were systematically optimized. Under the optimum conditions, good linearity ranging from 27.03 to 353.47 μg/kg was obtained for the analyte. Limit of detection and quantitation values were found to be 6.2 and 21 μg/kg (mass base), respectively. The relative standard deviation was calculated as 6.9% for six replicate measurements of the lowest concentration of the calibration plot. Satisfactory recovery results were calculated in the range of 97–100% for human plasma and urine samples spiked at five different concentrations.  相似文献   
147.
Herein, the oxidative polymerization of 4-methyl catechol using different oxidants including NaOCl, H2O2, and air were reported. Potassium hydroxide solution was used as the reaction solvent and polymerization studies were carried out between 323 and 363 K. Optimum reaction conditions of the polymerization were established and NaOCl was found as the most active oxidant. The structure and characterization of the polymer using FT-IR, ultraviolet–visible (UV–Vis), 1H-NMR, 13C-NMR, thermogravimetry and size exclusion chromatography were confirmed. In addition, the relationship between molar mass distribution of polymer and kinetics parameters such as activation energy, pre-exponential factor of decomposition process was investigated. For this purpose, methods based on multiple heating rates such as Flynn–Wall–Ozawa, Friedman, Tang, Kissinger–Akahira–Sunose, and Kissinger were used. The results obtained show that activation energy increased with an increase of molar mass.  相似文献   
148.
Addition of LDA to a mixture of trimethylborate and dibromomethane in THF at a temperature of -78°C leads to the formation of dibromomethyllithium and its capture by borate ester. ClB(OMe)(2) converts the resulting borate salt to dimethoxy(dibromomethyl)borane 2. N,N-Dimethylamino(methoxy)(dibromomethyl)borane 3 and N,N-bis(dimethylamino)(dibromomethyl)borane 4 were prepared by an amination reaction between N,N-dimethylaminotrimethylsilane and dimethoxy(dibromomethyl)borane 2. To obtain dichlorotrimethylsilylmethylborane 7 not containing the α-halomethyl group, N,N-bis(dimethylamino)(trimethylsilylmethyl)borane 5 was first obtained from the reaction of ClB(NMe(2))(2) with an organolithium reagent. Dimethoxy(trimethylsilylmethyl)borane 6 was then prepared by methoxylation of compound 5. Finally, compound 7 was prepared by chlorination of 6 using BCl(3). The chemical structures of these compounds were determined using (13)C, (1)H, (11)B NMR and GC/MS/MS techniques.  相似文献   
149.
150.
The effects of vowels on voice perturbation measures   总被引:1,自引:0,他引:1  
This study examines voice perturbation parameters of the sustained [a] in English and of the eight vowels in Turkish to discover whether any difference exists between these languages, and whether a correlation exists between voice perturbation parameters and articulatory and acoustic properties of the Turkish vowels. Eight Turkish vowels uttered by 26 healthy nonsmoker volunteer males who are native Turkish speakers were compared with a voice database that includes samples of normal and disordered voices belonging to American English speakers. Fundamental frequencies, the first and second formants, and perturbation parameters, such as jitter percent, pitch perturbation quotient, shimmer percent, and amplitude perturbation quotient of the sustained vowels, were measured. Also, the first and second formants of the sustained [a] in English were measured, and other parameters have been obtained from the database. When the voice perturbation parameters in Turkish and English were compared, statistically significant differences were not found. However, when Turkish vowels compared with each other, statistically significant differences were found among perturbation values. Categorical comparisons of the Turkish vowels like high-low, rounded-unrounded, and front-back revealed significant differences in perturbation values. In correlation analysis, a weak linear inverse relation between jitter percent and the first formant (r=-0.260, p<0.05) was found.  相似文献   
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